在对4G系统OFDM技术分析的基础上,针对5G候选波形Filtered-OFDM技术的特点,研究了2个子带情况下的系统性能。仿真结果表明,Filtered-OFDM系统的带外泄露比OFDM系统约低40 d B;当滤波器长度更长时,系统能获得较低的误码率,但滤波器设计...在对4G系统OFDM技术分析的基础上,针对5G候选波形Filtered-OFDM技术的特点,研究了2个子带情况下的系统性能。仿真结果表明,Filtered-OFDM系统的带外泄露比OFDM系统约低40 d B;当滤波器长度更长时,系统能获得较低的误码率,但滤波器设计更加复杂;保护间隔越大,两个子带数据的干扰越小,同时浪费了更多的频谱资源;调制阶数越高,误码率越高。在实际设计中,应该综合考虑这些因素的影响。展开更多
To deal with the expected diversification on traffic types, the fundamental waveform of the upcoming5 G standard must be sufficiently flexible. In the 4th generation wireless networks(e.g., cellular LTE and Wi- Fi802....To deal with the expected diversification on traffic types, the fundamental waveform of the upcoming5 G standard must be sufficiently flexible. In the 4th generation wireless networks(e.g., cellular LTE and Wi- Fi802.11ac), orthogonal frequency division multiplexing(OFDM) has been widely adopted to combat frequency selectivity and thus improve the spectrum efficiency. Holding various advantages such as backward compatibility with LTE, ease of hardware implementation, time-localized low-latency transmission and straightforward combination with multi-antenna transmission, OFDM will remain as an important waveform candidate for 5G. However,OFDM alone appears to be insufficient in terms of the requirements faced by 5G waveform, such as high flexibility to accommodate different waveform numerologies for an efficient support of diversified traffic types and channel characteristics. In this work, we present a new waveform format, named as filtered-OFDM(f-OFDM) and illustrate its potential and benefits for serving as the underlying waveform of 5G.展开更多
With the increasing demand for indoor localization,indoor location based on Wi-Fi has gained wide attention due to its convenience of access.In this paper,we propose a new multi-feature fusion convolutional neural net...With the increasing demand for indoor localization,indoor location based on Wi-Fi has gained wide attention due to its convenience of access.In this paper,we propose a new multi-feature fusion convolutional neural network(CNN)based on channel state information(CSI)images,which contains more feature information by constituting a new CSI image with amplitude and angle of arrival information of CSI information collected at known points.Moreover,the global mean filtering(GMC)algorithm with median filtering proposed in this paper is used to filter and reduce the noise of CSI images to obtain clearer images for network training.To extract more features from the CSI images,the traditional single-channel network is extended,and a two-channel design is introduced to extract feature information between adjacent subcarriers.Experimental evaluation is performed in a typical indoor environment,and the proposed method is experimentally proven to have good localization performance.展开更多
This study systematically investigated the influence of deposition rate on the structure,broadband opti⁃cal properties(1.0-13.0μm),and stress characteristics of Germanium(Ge)films.Additionally,a method for enhancing ...This study systematically investigated the influence of deposition rate on the structure,broadband opti⁃cal properties(1.0-13.0μm),and stress characteristics of Germanium(Ge)films.Additionally,a method for enhancing the performance of infrared filters based on rate-modulated deposition of Ge films was proposed.The optical absorption of Ge films in the short-wave infrared(SWIR)and long-wave infrared(LWIR)bands can be effectively reduced by modulating the deposition rate.As the deposition rate increases,the Ge films maintain an amorphous structure.The optical constants of the films in the 1.0-2.5μm and 2.5-13.0μm bands were precisely determined using the Cody-Lorentz model and the classical Lorentz oscillator model,respectively.Notably,high⁃er deposition rates result in a gradual increase in the refractive index.The extinction coefficient increases with the deposition rate in the SWIR region,attributed to the widening of the Urbach tail,while it decreases in the LWIR region due to the reduced absorption caused by the Ge-O stretching mode.Additionally,the films exhibit a tensile stress that decreases with increasing deposition rate.Finally,the effectiveness of the proposed fabrication method for an infrared filter with Ge films deposited at an optimized rate was demonstrated through practical examples.This work provides theoretical and technical support for the application of Ge films in high-performance infrared filters.展开更多
The Savitzky-Golay(SG)filter,which employs polynomial least-squares approximations to smooth data and estimate derivatives,is widely used for processing noisy data.However,noise suppression by the SG filter is recogni...The Savitzky-Golay(SG)filter,which employs polynomial least-squares approximations to smooth data and estimate derivatives,is widely used for processing noisy data.However,noise suppression by the SG filter is recognized to be limited at data boundaries and high frequencies,which can significantly reduce the signal-to-noise ratio(SNR).To solve this problem,a novel method synergistically integrating Principal Component Analysis(PCA)with SG filtering is proposed in this paper.This approach avoids the is-sue of excessive smoothing associated with larger window sizes.The proposed PCA-SG filtering algorithm was applied to a CO gas sensing system based on Cavity Ring-Down Spectroscopy(CRDS).The perform-ance of the PCA-SG filtering algorithm is demonstrated through comparison with Moving Average Filtering(MAF),Wavelet Transformation(WT),Kalman Filtering(KF),and the SG filter.The results demonstrate that the proposed algorithm exhibits superior noise reduction capabilities compared to the other algorithms evaluated.The SNR of the ring-down signal was improved from 11.8612 dB to 29.0913 dB,and the stand-ard deviation of the extracted ring-down time constant was reduced from 0.037μs to 0.018μs.These results confirm that the proposed PCA-SG filtering algorithm effectively improves the smoothness of the ring-down curve data,demonstrating its feasibility.展开更多
Accurate estimation of the State of Charge(SOC),State of Health(SOH),and Terminal Resistance(TR)is crucial for the effective operation of Battery Management Systems(BMS)in lithium-ion batteries.This study conducts a c...Accurate estimation of the State of Charge(SOC),State of Health(SOH),and Terminal Resistance(TR)is crucial for the effective operation of Battery Management Systems(BMS)in lithium-ion batteries.This study conducts a comprehensive comparative analysis of four Kalman filter variants Extended Kalman Filter(EKF),Extended Kalman-Bucy Filter(EKBF),Unscented Kalman Filter(UKF),and Unscented Kalman-Bucy Filter(UKBF)under varying battery parameter conditions.These include temperature fluctuation,self-discharge,current direction,cell capacity,process noise,and measurement noise.Our findings reveal significant variations in the performance of SOC and SOH predictions across filters,emphasizing that UKF demonstrates superior robustness to noise,while EKF performs better under accurate system dynamics.The study underscores the need for adaptive filtering strategies that can dynamically adjust to evolving battery parameters,thereby enhancing BMS reliability and extending battery lifespan.展开更多
文摘在对4G系统OFDM技术分析的基础上,针对5G候选波形Filtered-OFDM技术的特点,研究了2个子带情况下的系统性能。仿真结果表明,Filtered-OFDM系统的带外泄露比OFDM系统约低40 d B;当滤波器长度更长时,系统能获得较低的误码率,但滤波器设计更加复杂;保护间隔越大,两个子带数据的干扰越小,同时浪费了更多的频谱资源;调制阶数越高,误码率越高。在实际设计中,应该综合考虑这些因素的影响。
文摘To deal with the expected diversification on traffic types, the fundamental waveform of the upcoming5 G standard must be sufficiently flexible. In the 4th generation wireless networks(e.g., cellular LTE and Wi- Fi802.11ac), orthogonal frequency division multiplexing(OFDM) has been widely adopted to combat frequency selectivity and thus improve the spectrum efficiency. Holding various advantages such as backward compatibility with LTE, ease of hardware implementation, time-localized low-latency transmission and straightforward combination with multi-antenna transmission, OFDM will remain as an important waveform candidate for 5G. However,OFDM alone appears to be insufficient in terms of the requirements faced by 5G waveform, such as high flexibility to accommodate different waveform numerologies for an efficient support of diversified traffic types and channel characteristics. In this work, we present a new waveform format, named as filtered-OFDM(f-OFDM) and illustrate its potential and benefits for serving as the underlying waveform of 5G.
基金supported by Natural Science Foundation of Hunan Province under Grant(NO:2021JJ31142).
文摘With the increasing demand for indoor localization,indoor location based on Wi-Fi has gained wide attention due to its convenience of access.In this paper,we propose a new multi-feature fusion convolutional neural network(CNN)based on channel state information(CSI)images,which contains more feature information by constituting a new CSI image with amplitude and angle of arrival information of CSI information collected at known points.Moreover,the global mean filtering(GMC)algorithm with median filtering proposed in this paper is used to filter and reduce the noise of CSI images to obtain clearer images for network training.To extract more features from the CSI images,the traditional single-channel network is extended,and a two-channel design is introduced to extract feature information between adjacent subcarriers.Experimental evaluation is performed in a typical indoor environment,and the proposed method is experimentally proven to have good localization performance.
基金Supported by the National Natural Science Foundation of China(62275053,62275256)the National key Research and Development Program of China(2021YFB3701500)+1 种基金the Youth Innovation Promotion Association of the Chinese Academy of Sciences(2023248)the Eastern Talent Plan Youth Project 2022,the Shanghai Key Laboratory of Optical Coatings and Spectral Modulation(23dz2260500).
文摘This study systematically investigated the influence of deposition rate on the structure,broadband opti⁃cal properties(1.0-13.0μm),and stress characteristics of Germanium(Ge)films.Additionally,a method for enhancing the performance of infrared filters based on rate-modulated deposition of Ge films was proposed.The optical absorption of Ge films in the short-wave infrared(SWIR)and long-wave infrared(LWIR)bands can be effectively reduced by modulating the deposition rate.As the deposition rate increases,the Ge films maintain an amorphous structure.The optical constants of the films in the 1.0-2.5μm and 2.5-13.0μm bands were precisely determined using the Cody-Lorentz model and the classical Lorentz oscillator model,respectively.Notably,high⁃er deposition rates result in a gradual increase in the refractive index.The extinction coefficient increases with the deposition rate in the SWIR region,attributed to the widening of the Urbach tail,while it decreases in the LWIR region due to the reduced absorption caused by the Ge-O stretching mode.Additionally,the films exhibit a tensile stress that decreases with increasing deposition rate.Finally,the effectiveness of the proposed fabrication method for an infrared filter with Ge films deposited at an optimized rate was demonstrated through practical examples.This work provides theoretical and technical support for the application of Ge films in high-performance infrared filters.
文摘The Savitzky-Golay(SG)filter,which employs polynomial least-squares approximations to smooth data and estimate derivatives,is widely used for processing noisy data.However,noise suppression by the SG filter is recognized to be limited at data boundaries and high frequencies,which can significantly reduce the signal-to-noise ratio(SNR).To solve this problem,a novel method synergistically integrating Principal Component Analysis(PCA)with SG filtering is proposed in this paper.This approach avoids the is-sue of excessive smoothing associated with larger window sizes.The proposed PCA-SG filtering algorithm was applied to a CO gas sensing system based on Cavity Ring-Down Spectroscopy(CRDS).The perform-ance of the PCA-SG filtering algorithm is demonstrated through comparison with Moving Average Filtering(MAF),Wavelet Transformation(WT),Kalman Filtering(KF),and the SG filter.The results demonstrate that the proposed algorithm exhibits superior noise reduction capabilities compared to the other algorithms evaluated.The SNR of the ring-down signal was improved from 11.8612 dB to 29.0913 dB,and the stand-ard deviation of the extracted ring-down time constant was reduced from 0.037μs to 0.018μs.These results confirm that the proposed PCA-SG filtering algorithm effectively improves the smoothness of the ring-down curve data,demonstrating its feasibility.
基金supported by the Royal Academy of Engineering,UK,in the scheme of Distinguished International Associate(DIA-2424-5-134).
文摘Accurate estimation of the State of Charge(SOC),State of Health(SOH),and Terminal Resistance(TR)is crucial for the effective operation of Battery Management Systems(BMS)in lithium-ion batteries.This study conducts a comprehensive comparative analysis of four Kalman filter variants Extended Kalman Filter(EKF),Extended Kalman-Bucy Filter(EKBF),Unscented Kalman Filter(UKF),and Unscented Kalman-Bucy Filter(UKBF)under varying battery parameter conditions.These include temperature fluctuation,self-discharge,current direction,cell capacity,process noise,and measurement noise.Our findings reveal significant variations in the performance of SOC and SOH predictions across filters,emphasizing that UKF demonstrates superior robustness to noise,while EKF performs better under accurate system dynamics.The study underscores the need for adaptive filtering strategies that can dynamically adjust to evolving battery parameters,thereby enhancing BMS reliability and extending battery lifespan.
